The present invention generally relates to processing of materials for growth of crystals. More particularly, the present invention provides a transparent gallium-containing nitride crystal synthesized by an ammonobasic or ammonoacidic technique. The present invention provides methods suitable for synthesis of polycrystalline nitride materials, as well as other crystals and materials. Such crystals and materials include, but are not limited to, GaN, AlN, InN, InGaN, AlGaN, and AlInGaN, and for manufacture of bulk or patterned substrates. Such bulk or patterned substrates can be used for a variety of applications including optoelectronic devices, lasers, light emitting diodes, solar cells, photoelectrochemical water splitting and hydrogen generation, photodetectors, integrated circuits, and transistors.
Gallium nitride containing crystalline materials serve as substrates for manufacture of conventional optoelectronic devices, such as blue light emitting diodes and lasers. Such optoelectronic devices have been commonly manufactured on sapphire or silicon carbide substrates that differ in composition from the deposited nitride layers. In the conventional Metal-Organic Chemical Vapor Deposition (MOCVD) method, deposition of GaN is performed from ammonia and organometallic compounds in the gas phase. Although successful, conventional growth rates achieved make it difficult to provide a bulk layer of GaN material. Additionally, dislocation densities are also high and lead to poorer optoelectronic device performance.
Reasonably high quality, substantially transparent substrates comprising bulk gallium nitride are available commercially, however, in most cases, these substrates are synthesized by hydride vapor phase epitaxy (HVPE), which is relatively expensive.
What is needed is a method for low-cost manufacturing of transparent nitride materials that are transparent, colorless, and of high crystallographic quality.